Anaphase The cell to the left is a nice mid anaphase. Next, the chromosomes were entwined to represent synapsis. Untreated cells should be able to divide normally; while colchicine treated cells will die of microtubule degradation. For an organism to grow, mature and maintain tissue, new cells must be made. Anaphase begins when the chromatids are separated and pulled to opposite poles. The centromeres break thus creating a two separate identical chromosomes. Antimitotic Effect of Colchicine from Six Different Species of Gloriosa in Onion Roots Allium cepa.
Observe the condensing chromosomes dark regions in the cell on the left below in early prophase. What parts of plants are most impacted by mitosis? Cite in Scientific Research: Nedungadi P. This level position is called the metaphase plate. In plant cells cytokinesis involves the formation of a cell plate. When observing the whitefish embryo cells for the stage of telophase, the overall shape stayed the same except for one cell which is currently in the telophase stage.
The tip was then covered with 1 drop of toluidine blue solution and left for 2 minutes. Place two more drops of stain upon the root tip and wait for another two minutes. Prior to mitosis is interphase when the cell grows and duplicates all organelles , and post-mitosis is cytokenesis when the cell membrane pinches together to split the actual cell in half to form two cells animal or when a cell plate is formed to separate the cells plant. Alternatives to garlic include onions, hyacinths or seedlings of beans or peas — as long as they are healthy and fast growing. In prophase, the chromatin thicken into distinct chromosomes and the nuclear envelope breaks open releasing them into the cytoplasm.
Avoid moving the coverslip from side to side. Introduction and Background In the early 1880s, the German anatomist Walther Flemming observed the fibrous structures of spindle fibers and created the term mitosis, from the Greek word for thread, to describe the actions of spindle fibers in a dividing cell. Cytokinesis in plant cell occur as the cell plate forms, thus dividing the daughter cell. By reading the discussion and review we were able to answer questions in lab manual about mitosis. The coverslip was then added. In addition, I proved my hypothesis correct, as a majority of the cells I identified were in interphase. These cell divides either mitotically or meiotically , which is based on its location.
A cell in metaphase: Anaphase is the stage of mitosis when cohesin, the protein holding together sister chromatids breaks down and the chromatids that make up the chromosome separate and are pulled to opposite ends of the cell by the microtubules. Exercise 3B is a study of meiosis. Let stain soak into root tip for two minutes. Hypothesis It can be predicted that all somatic cells will undergo all the stages of mitosis multiple times in their lifetime, that the viewed will be able to see the chromosomes at one stage of mitosis. That is where the cells split and is where nuclear replication is the most frequent.
I identified and classified the cells based on their stage in mitosis: interphase, prophase, prometaphase, metaphase, anaphase, and telophase, as depicted below in Figure 3 and Figure 4 Figure 3: Figure 4: 4. I focused the microscope on the 4X setting with the onion root tip in view, making sure the diaphragm again was at its widest setting. Meiosis is more complex and involves two nuclear divisions. Each of 10 groups will complete the experiment on their own and all data will be combined at the end. These cells were stained blue and red, in contrast to the cells in Figure 5. The mitotic index is calculated like this: The duration of each stage of mitosis has been recorded and the data see table below could be used to compare the observed frequencies of the different stages as recorded by students. In a folded paper towel, I took the eraser end of a pencil and pressed it firmly on top of the root tip beneath the cover slip.
Also, the stages of metaphase, anaphase, and telophase pass by very quickly so cells are in these stages for a short period of time. Then, the final stage is telophase. The sample was taken from the stem. We concluded that the further away from the root, the less mitotic index there will be. The location of the apical meristem root tissue is displayed in Figure 2 below.
This is a period of rapid growth and numerous cellular divisions where mitosis can be observed. In this stage the chromosomes reached the centrioles and a nuclear membrane begins to form around each nucleus. Mitosis is only one part of the cell cycle. In this experiment we will categorize and count the cells to compute the mitotic index of the total root area. Life Science 1 Laboratory Student Report and Study Guide. The links between the cellulose walls of plant cells are broken down by the treatment with hydrochloric acid.
The mitotic index can be used in agriculture to determine what plants can be planted in what season and what kind of climate they can withstand. What did you compute to be the mitotic index of the combined six slides assume there are 54 total cells? Cut off four root tips, each approximately 1 cm long; Fill test tube 3cm full of fixative. I located the meristem root tissue of the onion root tip and switched the microscope to the 40X measure, in which cells were visible. Interphase consist of three stages call G1, S and G2. We examined and recorded the stage each cell was in for 387 Cells and calculated the percentage of cells in each phase.
Crossing over can be observed in the arrangement and color of these asci. The tip is the narrow, pointy end with an opaque white color. Hypothesis-There is no hypothesis for this experiment Procedure-Review discussion about mitosis, examine the six photos of the mitosis of onion root on the worksheet provided. The stage that the cell is currently in is anaphase. Cell is known as unit of life. Overall, I have learned that onion root tip cells and whitefish embryo cells are constantly reproducing and creating new cells, how to calculate the percentage of cells in a stage of mitosis, and, finally, that the chromosomes are visible using only a light microscope. The hemoglobin then reacts with the nitrites to form Methemoglobin.